Public access defibrillators (PADs) are designed to be used by lay caregivers and/or emergency workers such as EMTs and firefighters to resuscitate victims of cardiac arrest. PADs are likely to be stored in public places, where they can be readily located and used by these caregivers and emergency workers. They may hang on walls, be stored on shelves, or even in the trunks of vehicles.
Each PAD typically includes a defibrillator unit and a pair of disposable electrodes. The pair of electrodes is stored inside an electrode package or pouch (or each electrode within a separate package). The electrodes must be removed from the package, applied to the victim""s chest, and the electrode cables connected to the defibrillator unit. EKG signals detected through the electrodes are analyzed by electronics within the defibrillator unit, to determine the cardiac condition of the victim. If defibrillation is required a defibrillation pulse is delivered through the same electrodes.
Depending on the design of the PAD, the electrode package may be stored inside the defibrillation unit, e.g., inside a cover plate, to protect it from damage that might occur if it were exposed.
The electrodes have a limited shelf life, and must be periodically replaced. For example, electrodes containing an aqueous gel will eventually dry out or corrode the metallic elements of the electrode. As a typical PAD will not often be usedxe2x80x94indeed, it can be expected that most PADs will never be usedxe2x80x94it cannot be assumed that electrodes will be used, and thus replaced, prior to expiration of their shelf life. Instead it is typical for PADs to be periodically inspected to be sure that their electrodes have not expired. This is typically done by reading the expiration date from a label on the exterior of the electrode package.
In a first aspect, the invention features a defibrillator in which electrodes with a limited shelf life are stored largely out of view from the exterior of the unit, but the expiration date or other marking indicative of expiration or failure is positioned so as to be visible from the exterior of the defibrillation unit.
In preferred implementations, one or more of the following features may be incorporated. The defibrillation unit may have an opening through which a tab connected to the electrodes extends, with the expiration date or other marking positioned so as to be on the visible portion of the tab. The electrodes may be contained within one or two electrode packages, and a tab may extend from one or both of the packages. A single package may contain both electrodes, and a tab may extend from the single package. The defibrillation unit may include a cover and a base unit to which the cover is attached, the electrodes may be stored between the cover and the base unit, and the expiration date or other marking may be positioned on a tab extending from the electrodes to the exterior of the defibrillation unit.
In a second aspect, the invention features a fracturable member attached to the defibrillation unit so that opening the defibrillation unit requires fracturing the member, thereby providing an indication of whether the unit has been opened.
In preferred implementations, one or more of the following features may be incorporated. The fracturable member may have a visible portion carrying the expiration date or other marking indicative of electrode failure or expiration. The defibrillation unit may have a cover and a base unit to which the cover is attached, and opening the cover will fracture the member. The fracturable member may be an elongated band, and the band may be adhesively attached to at least one portion of the defibrillation unit. The band and adhesive attachment may be configured so that the band will fracture if an effort is made to detach the band at a location at which it is adhesively attached to the defibrillation unit. The fracturable member may be configured to tear if the defibrillation unit is opened.
In a third aspect, the invention features a defibrillator in which electrodes are stored between a cover and a base unit of the defibrillator, and in which the electrodes are releasably attached to the inside of the cover, so that when the cover is removed from the base unit the electrodes remain with the cover.
In preferred implementations, one or more of the following features may be incorporated. The electrodes may be contained within at least one package, and the releasable attachment of the electrodes to the inside of the cover may be provided by releasable attachment of the package to the inside of the cover. At least one tab member may extend from the electrode package, and the tab member may be releasably attached to the inside of the cover. The tab or elongated band on which expiration or other marking is carried may also serve as the releasable connection of the electrode package to the cover. The tab may extend through an opening in the cover, and may have tapered wings that require less force to insert into the opening in the cover than to remove from the opening.
In its various aspects, and preferred embodiments, the invention has numerous advantages (not all of which are present in all aspects and embodiments). Users are able to readily ascertain whether the electrodes have expired, and whether the defibrillator has been tampered with. This reduces the time required for routine inspection of the defibrillator. Because inspection for electrode expiration can be done without opening the cover of the defibrillator, and without handling the electrode package, the likelihood of premature electrode failure from repeated handling is greatly reduced. It can be readily ascertained whether the defibrillator has been opened or tampered with. The electrode package is conveniently held adjacent the inside of the cover as it is removed, so that it does not obscure the controls of the unit.
Other features of the invention will be apparent from the following detailed description, including the drawings, and from the claims.